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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 6830 (Obsoleted by RFC 9300, RFC 9301) ** Downref: Normative reference to an Experimental RFC: RFC 6831 ** Downref: Normative reference to an Experimental RFC: RFC 6836 ** Downref: Normative reference to an Experimental RFC: RFC 6837 ** Downref: Normative reference to an Experimental RFC: RFC 8060 ** Downref: Normative reference to an Experimental RFC: RFC 8111 ** Obsolete normative reference: RFC 8113 (Obsoleted by RFC 9304) == Outdated reference: A later version (-19) exists of draft-ermagan-lisp-nat-traversal-13 == Outdated reference: A later version (-13) exists of draft-ietf-lisp-eid-mobility-01 == Outdated reference: A later version (-15) exists of draft-ietf-lisp-introduction-13 == Outdated reference: A later version (-15) exists of draft-ietf-lisp-mn-01 == Outdated reference: A later version (-38) exists of draft-ietf-lisp-rfc6830bis-07 == Outdated reference: A later version (-29) exists of draft-ietf-lisp-sec-14 == Outdated reference: A later version (-09) exists of draft-ietf-lisp-signal-free-multicast-07 == Outdated reference: A later version (-02) exists of draft-rodrigueznatal-lisp-pubsub-01 Summary: 7 errors (**), 0 flaws (~~), 10 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group V. Fuller 3 Internet-Draft D. Farinacci 4 Intended status: Standards Track Cisco Systems 5 Expires: June 18, 2018 A. Cabellos (Ed.) 6 UPC/BarcelonaTech 7 December 15, 2017 9 Locator/ID Separation Protocol (LISP) Control-Plane 10 draft-ietf-lisp-rfc6833bis-07 12 Abstract 14 This document describes the Control-Plane and Mapping Service for the 15 Locator/ID Separation Protocol (LISP), implemented by two new types 16 of LISP-speaking devices -- the LISP Map-Resolver and LISP Map-Server 17 -- that provides a simplified "front end" for one or more Endpoint ID 18 to Routing Locator mapping databases. 20 By using this control-plane service interface and communicating with 21 Map-Resolvers and Map-Servers, LISP Ingress Tunnel Routers (ITRs) and 22 Egress Tunnel Routers (ETRs) are not dependent on the details of 23 mapping database systems, which facilitates modularity with different 24 database designs. Since these devices implement the "edge" of the 25 LISP infrastructure, connect directly to LISP-capable Internet end 26 sites, and comprise the bulk of LISP-speaking devices, reducing their 27 implementation and operational complexity should also reduce the 28 overall cost and effort of deploying LISP. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on June 18, 2018. 47 Copyright Notice 49 Copyright (c) 2017 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 66 3. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4 67 4. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 5 68 5. LISP IPv4 and IPv6 Control-Plane Packet Formats . . . . . . . 7 69 5.1. LISP Control Packet Type Allocations . . . . . . . . . . 9 70 5.2. Map-Request Message Format . . . . . . . . . . . . . . . 10 71 5.3. EID-to-RLOC UDP Map-Request Message . . . . . . . . . . . 13 72 5.4. Map-Reply Message Format . . . . . . . . . . . . . . . . 15 73 5.5. EID-to-RLOC UDP Map-Reply Message . . . . . . . . . . . . 19 74 5.6. Map-Register Message Format . . . . . . . . . . . . . . . 22 75 5.7. Map-Notify/Map-Notify-Ack Message Format . . . . . . . . 25 76 5.8. Encapsulated Control Message Format . . . . . . . . . . . 26 77 6. Interactions with Other LISP Components . . . . . . . . . . . 28 78 6.1. ITR EID-to-RLOC Mapping Resolution . . . . . . . . . . . 28 79 6.2. EID-Prefix Configuration and ETR Registration . . . . . . 29 80 6.3. Map-Server Processing . . . . . . . . . . . . . . . . . . 31 81 6.4. Map-Resolver Processing . . . . . . . . . . . . . . . . . 31 82 6.4.1. Anycast Map-Resolver Operation . . . . . . . . . . . 32 83 7. Security Considerations . . . . . . . . . . . . . . . . . . . 32 84 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 85 8.1. LISP Packet Type Codes . . . . . . . . . . . . . . . . . 33 86 8.2. LISP ACT and Flag Fields . . . . . . . . . . . . . . . . 33 87 8.3. LISP Address Type Codes . . . . . . . . . . . . . . . . . 34 88 8.4. LISP Algorithm ID Numbers . . . . . . . . . . . . . . . . 34 89 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 90 9.1. Normative References . . . . . . . . . . . . . . . . . . 34 91 9.2. Informative References . . . . . . . . . . . . . . . . . 36 92 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 39 93 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 39 94 B.1. Changes to draft-ietf-lisp-rfc6833bis-07 . . . . . . . . 39 95 B.2. Changes to draft-ietf-lisp-rfc6833bis-06 . . . . . . . . 39 96 B.3. Changes to draft-ietf-lisp-rfc6833bis-05 . . . . . . . . 40 97 B.4. Changes to draft-ietf-lisp-rfc6833bis-04 . . . . . . . . 40 98 B.5. Changes to draft-ietf-lisp-rfc6833bis-03 . . . . . . . . 40 99 B.6. Changes to draft-ietf-lisp-rfc6833bis-02 . . . . . . . . 40 100 B.7. Changes to draft-ietf-lisp-rfc6833bis-01 . . . . . . . . 41 101 B.8. Changes to draft-ietf-lisp-rfc6833bis-00 . . . . . . . . 41 102 B.9. Changes to draft-farinacci-lisp-rfc6833bis-00 . . . . . . 41 103 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42 105 1. Introduction 107 The Locator/ID Separation Protocol [I-D.ietf-lisp-introduction] and 108 [I-D.ietf-lisp-rfc6830bis] specifies an architecture and mechanism 109 for replacing the addresses currently used by IP with two separate 110 name spaces: Endpoint IDs (EIDs), used within sites; and Routing 111 Locators (RLOCs), used on the transit networks that make up the 112 Internet infrastructure. To achieve this separation, LISP defines 113 protocol mechanisms for mapping from EIDs to RLOCs. In addition, 114 LISP assumes the existence of a database to store and propagate those 115 mappings globally. Several such databases have been proposed; among 116 them are the Content distribution Overlay Network Service for LISP 117 (LISP-CONS) [LISP-CONS], LISP-NERD (a Not-so-novel EID-to-RLOC 118 Database) [RFC6837], LISP Alternative Logical Topology (LISP+ALT) 119 [RFC6836], and LISP Delegated Database Tree (LISP-DDT) [RFC8111]. 121 The LISP Mapping Service defines two new types of LISP-speaking 122 devices: the Map-Resolver, which accepts Map-Requests from an Ingress 123 Tunnel Router (ITR) and "resolves" the EID-to-RLOC mapping using a 124 mapping database; and the Map-Server, which learns authoritative EID- 125 to-RLOC mappings from an Egress Tunnel Router (ETR) and publishes 126 them in a database. 128 This LISP Control-Plane Mapping Service can be used by many different 129 encapsulation-based or translation-based data-planes which include 130 but are not limited to the ones defined in LISP RFC 6830bis 131 [I-D.ietf-lisp-rfc6830bis], LISP-GPE [I-D.lewis-lisp-gpe], VXLAN 132 [RFC7348], and VXLAN-GPE [I-D.quinn-vxlan-gpe]. 134 Conceptually, LISP Map-Servers share some of the same basic 135 configuration and maintenance properties as Domain Name System (DNS) 136 [RFC1035] servers; likewise, Map-Resolvers are conceptually similar 137 to DNS caching resolvers. With this in mind, this specification 138 borrows familiar terminology (resolver and server) from the DNS 139 specifications. 141 Note that while this document assumes a LISP+ALT database mapping 142 infrastructure to illustrate certain aspects of Map-Server and Map- 143 Resolver operation, the Mapping Service interface can (and likely 144 will) be used by ITRs and ETRs to access other mapping database 145 systems as the LISP infrastructure evolves. 147 The LISP Mapping Service is an important component of the LISP 148 toolset. Issues and concerns about the deployment of LISP for 149 Internet traffic are discussed in [I-D.ietf-lisp-rfc6830bis]. 151 2. Requirements Notation 153 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 154 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 155 document are to be interpreted as described in [RFC2119]. 157 3. Definition of Terms 159 Map-Server: A network infrastructure component that learns of EID- 160 Prefix mapping entries from an ETR, via the registration mechanism 161 described below, or some other authoritative source if one exists. 162 A Map-Server publishes these EID-Prefixes in a mapping database. 164 Map-Request: A LISP Map-Request is a control-plane message to query 165 the mapping system to resolve an EID. A LISP Map-Request can also 166 be sent to an RLOC to test for reachability and to exchange 167 security keys between an encapsulator and a decapsulator. This 168 type of Map-Request is also known as an RLOC-Probe Request. 170 Map-Reply: A LISP Map-Reply is a control-plane message returned in 171 response to a Map-Request sent to the mapping system when 172 resolving an EID. A LISP Map-Reply can also be returned by a 173 decapsulator in response to a Map-Request sent by an encapsulator 174 to test for reachability. This type of Map-Reply is known as a 175 RLOC-Probe Reply. 177 Encapsulated Map-Request: A LISP Map-Request carried within an 178 Encapsulated Control Message (ECM), which has an additional LISP 179 header prepended. Sent to UDP destination port 4342. The "outer" 180 addresses are routable IP addresses, also known as RLOCs. Used by 181 an ITR when sending to a Map-Resolver and by a Map-Server when 182 forwarding a Map-Request to an ETR. 184 Map-Resolver: A network infrastructure component that accepts LISP 185 Encapsulated (ECM) Map-Requests, typically from an ITR, and 186 determines whether or not the destination IP address is part of 187 the EID namespace; if it is not, a Negative Map-Reply is returned. 188 Otherwise, the Map-Resolver finds the appropriate EID-to-RLOC 189 mapping by consulting a mapping database system. 191 Negative Map-Reply: A LISP Map-Reply that contains an empty 192 Locator-Set. Returned in response to a Map-Request if the 193 destination EID does not exist in the mapping database. 194 Typically, this means that the "EID" being requested is an IP 195 address connected to a non-LISP site. 197 Map-Register message: A LISP message sent by an ETR to a Map-Server 198 to register its associated EID-Prefixes. In addition to the set 199 of EID-Prefixes to register, the message includes one or more 200 RLOCs to reach ETR(s). The Map-Server uses these RLOCs when 201 forwarding Map-Requests (re-formatted as Encapsulated Map- 202 Requests). An ETR MAY request that the Map-Server answer Map- 203 Requests on its behalf by setting the "proxy Map-Reply" flag 204 (P-bit) in the message. 206 Map-Notify message: A LISP message sent by a Map-Server to an ETR 207 to confirm that a Map-Register has been received and processed. 208 An ETR requests that a Map-Notify be returned by setting the 209 "want-map-notify" flag (M-bit) in the Map-Register message. 210 Unlike a Map-Reply, a Map-Notify uses UDP port 4342 for both 211 source and destination. Map-Notify messages are also sent to ITRs 212 by Map-Servers when there are RLOC-set changes. 214 For definitions of other terms, notably Ingress Tunnel Router (ITR), 215 Egress Tunnel Router (ETR), and Re-encapsulating Tunnel Router (RTR), 216 refer to the LISP Data-Plane specification 217 [I-D.ietf-lisp-rfc6830bis]. 219 4. Basic Overview 221 A Map-Server is a device that publishes EID-Prefixes in a LISP 222 mapping database on behalf of a set of ETRs. When it receives a Map 223 Request (typically from an ITR), it consults the mapping database to 224 find an ETR that can answer with the set of RLOCs for an EID-Prefix. 225 To publish its EID-Prefixes, an ETR periodically sends Map-Register 226 messages to the Map-Server. A Map-Register message contains a list 227 of EID-Prefixes plus a set of RLOCs that can be used to reach the 228 ETRs. 230 When LISP+ALT is used as the mapping database, a Map-Server connects 231 to the ALT network and acts as a "last-hop" ALT-Router. Intermediate 232 ALT-Routers forward Map-Requests to the Map-Server that advertises a 233 particular EID-Prefix, and the Map-Server forwards them to the owning 234 ETR, which responds with Map-Reply messages. 236 When LISP-DDT [RFC8111] is used as the mapping database, a Map-Server 237 sends the final Map-Referral messages from the Delegated Database 238 Tree. 240 A Map-Resolver receives Encapsulated Map-Requests from its client 241 ITRs and uses a mapping database system to find the appropriate ETR 242 to answer those requests. On a LISP+ALT network, a Map-Resolver acts 243 as a "first-hop" ALT-Router. It has Generic Routing Encapsulation 244 (GRE) tunnels configured to other ALT-Routers and uses BGP to learn 245 paths to ETRs for different prefixes in the LISP+ALT database. The 246 Map-Resolver uses this path information to forward Map-Requests over 247 the ALT to the correct ETRs. On a LISP-DDT network [RFC8111], a Map- 248 Resolver maintains a referral-cache and acts as a "first-hop" DDT- 249 node. The Map-Resolver uses the referral information to forward Map- 250 Requests. 252 Note that while it is conceivable that a Map-Resolver could cache 253 responses to improve performance, issues surrounding cache management 254 will need to be resolved so that doing so will be reliable and 255 practical. As initially deployed, Map-Resolvers will operate only in 256 a non-caching mode, decapsulating and forwarding Encapsulated Map 257 Requests received from ITRs. Any specification of caching 258 functionality is left for future work. 260 Note that a single device can implement the functions of both a Map- 261 Server and a Map-Resolver, and in many cases the functions will be 262 co-located in that way. Also, there can be ALT-only nodes and DDT- 263 only nodes, when LISP+ALT and LISP-DDT are used, respectively, to 264 connect Map-Resolvers and Map-Servers together to make up the Mapping 265 System. 267 Detailed descriptions of the LISP packet types referenced by this 268 document may be found in [I-D.ietf-lisp-rfc6830bis]. 270 5. LISP IPv4 and IPv6 Control-Plane Packet Formats 272 The following UDP packet formats are used by the LISP control plane. 274 0 1 2 3 275 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 276 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 277 |Version| IHL |Type of Service| Total Length | 278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 279 | Identification |Flags| Fragment Offset | 280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 | Time to Live | Protocol = 17 | Header Checksum | 282 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 283 | Source Routing Locator | 284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 285 | Destination Routing Locator | 286 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 287 / | Source Port | Dest Port | 288 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 \ | UDP Length | UDP Checksum | 290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 291 | | 292 | LISP Message | 293 | | 294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 0 1 2 3 297 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 299 |Version| Traffic Class | Flow Label | 300 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 301 | Payload Length | Next Header=17| Hop Limit | 302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 303 | | 304 + + 305 | | 306 + Source Routing Locator + 307 | | 308 + + 309 | | 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 | | 312 + + 313 | | 314 + Destination Routing Locator + 315 | | 316 + + 317 | | 318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 319 / | Source Port | Dest Port | 320 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 \ | UDP Length | UDP Checksum | 322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 323 | | 324 | LISP Message | 325 | | 326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 When a UDP Map-Request, Map-Register, or Map-Notify (when used as a 329 notification message) are sent, the UDP source port is chosen by the 330 sender and the destination UDP port number is set to 4342. When a 331 UDP Map-Reply Map-Notify (when used as an acknowledgement to a Map- 332 Register), or Map-Notify-Ack are sent, the source UDP port number is 333 set to 4342 and the destination UDP port number is copied from the 334 source port of either the Map-Request or the invoking data packet. 335 Implementations MUST be prepared to accept packets when either the 336 source port or destination UDP port is set to 4342 due to NATs 337 changing port number values. 339 The 'UDP Length' field will reflect the length of the UDP header and 340 the LISP Message payload. 342 The UDP checksum is computed and set to non-zero for all messages 343 sent to or from port 4342. It MUST be checked on receipt, and if the 344 checksum fails, the control message MUST be dropped. 346 The format of control messages includes the UDP header so the 347 checksum and length fields can be used to protect and delimit message 348 boundaries. 350 5.1. LISP Control Packet Type Allocations 352 This section defines the LISP control message formats and summarizes 353 for IANA the LISP Type codes assigned by this document. For 354 completeness, this document references the LISP Shared Extension 355 Message assigned by [RFC8113]. Message type definitions are: 357 Reserved: 0 b'0000' 358 LISP Map-Request: 1 b'0001' 359 LISP Map-Reply: 2 b'0010' 360 LISP Map-Register: 3 b'0011' 361 LISP Map-Notify: 4 b'0100' 362 LISP Map-Notify-Ack: 5 b'0101' 363 LISP Map-Referral: 6 b'0110' 364 LISP Encapsulated Control Message: 8 b'1000' 365 Not Assigned 9-14 b'1001'- b'1110' 366 LISP Shared Extension Message: 15 b'1111' [RFC8113] 368 Values in the "Not Assigned" range can be assigned according to 369 procedures in [RFC8126]. Documents that request for a new LISP 370 packet type MAY indicate a preferred value in Section 8.3. 372 Protocol designers experimenting with new message formats SHOULD use 373 the LISP Shared Extension Message Type and request a [RFC8113] sub- 374 type assignment. 376 All LISP control-plane messages use Address Family Identifiers (AFI) 377 [AFI] or LISP Canonical Address Format (LCAF) [RFC8060] formats to 378 encode either fixed or variable length addresses. This includes 379 explicit fields in each control message or part of EID-records or 380 RLOC-records in commonly formatted messages. 382 The LISP control-plane describes how other data-planes can encode 383 messages to support the SMR and RLOC-probing procedures of the LISP 384 data-plane defined in [I-D.ietf-lisp-rfc6830bis]. This control-plane 385 specification itself does not offer such functionality and other 386 data-planes can use their own mechanisms that do not rely on the LISP 387 control-plane. 389 5.2. Map-Request Message Format 391 0 1 2 3 392 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 393 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 394 |Type=1 |A|M|P|S|p|s|m|I| Rsvd |L|D| IRC | Record Count | 395 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 396 | Nonce . . . | 397 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 398 | . . . Nonce | 399 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 400 | Source-EID-AFI | Source EID Address ... | 401 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 402 | ITR-RLOC-AFI 1 | ITR-RLOC Address 1 ... | 403 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 404 | ... | 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 | ITR-RLOC-AFI n | ITR-RLOC Address n ... | 407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 408 / | Reserved | EID mask-len | EID-Prefix-AFI | 409 Rec +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 \ | EID-Prefix ... | 411 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 412 | Map-Reply Record ... | 413 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 Packet field descriptions: 417 Type: 1 (Map-Request) 419 A: This is an authoritative bit, which is set to 0 for UDP-based Map- 420 Requests sent by an ITR. It is set to 1 when an ITR wants the 421 destination site to return the Map-Reply rather than the mapping 422 database system. 424 M: This is the map-data-present bit. When set, it indicates that a 425 Map-Reply Record segment is included in the Map-Request. 427 P: This is the probe-bit, which indicates that a Map-Request SHOULD 428 be treated as a Locator reachability probe. The receiver SHOULD 429 respond with a Map-Reply with the probe-bit set, indicating that 430 the Map-Reply is a Locator reachability probe reply, with the 431 nonce copied from the Map-Request. See RLOC-Probing 432 [I-D.ietf-lisp-rfc6830bis] for more details. 434 S: This is the Solicit-Map-Request (SMR) bit. See Solicit-Map- 435 Request (SMRs) [I-D.ietf-lisp-rfc6830bis] for details. 437 p: This is the PITR bit. This bit is set to 1 when a PITR sends a 438 Map-Request. 440 s: This is the SMR-invoked bit. This bit is set to 1 when an xTR is 441 sending a Map-Request in response to a received SMR-based Map- 442 Request. 444 m: This is the LISP mobile-node m-bit. This bit is set by xTRs that 445 operate as a mobile node as defined in [I-D.ietf-lisp-mn]. 447 I: This is the xTR-ID bit. When this bit is set, what is appended to 448 the Map-Request is a 128-bit xTR router-ID. See LISP PubSub usage 449 procedures in [I-D.rodrigueznatal-lisp-pubsub] for details. 451 Rsvd: This field MUST be set to 0 on transmit and MUST be ignored on 452 receipt. 454 L: This is the local-xtr bit. It is used by an xTR in a LISP site to 455 tell other xTRs in the same site that it is local to the site. 456 That is, that it is part of the RLOC-set for the LISP site. 458 D: This is the dont-map-reply bit. It is used in the SMR procedure 459 described in [I-D.ietf-lisp-rfc6830bis]. When an xTR sends an SMR 460 Map-Request message, it doesn't need a Map-Reply returned. When 461 this bit is set, the receiver of the Map-Request does not return a 462 Map-Reply. 464 IRC: This 5-bit field is the ITR-RLOC Count, which encodes the 465 additional number of ('ITR-RLOC-AFI', 'ITR-RLOC Address') fields 466 present in this message. At least one (ITR-RLOC-AFI, ITR-RLOC- 467 Address) pair MUST be encoded. Multiple 'ITR-RLOC Address' fields 468 are used, so a Map-Replier can select which destination address to 469 use for a Map-Reply. The IRC value ranges from 0 to 31. For a 470 value of 0, there is 1 ITR-RLOC address encoded; for a value of 1, 471 there are 2 ITR-RLOC addresses encoded, and so on up to 31, which 472 encodes a total of 32 ITR-RLOC addresses. 474 Record Count: This is the number of records in this Map-Request 475 message. A record is comprised of the portion of the packet that 476 is labeled 'Rec' above and occurs the number of times equal to 477 Record Count. For this version of the protocol, a receiver MUST 478 accept and process Map-Requests that contain one or more records, 479 but a sender MUST only send Map-Requests containing one record. 480 Support for requesting multiple EIDs in a single Map-Request 481 message will be specified in a future version of the protocol. 483 Nonce: This is an 8-octet random value created by the sender of the 484 Map-Request. This nonce will be returned in the Map-Reply. The 485 security of the LISP mapping protocol critically depends on the 486 strength of the nonce in the Map-Request message. The nonce 487 SHOULD be generated by a properly seeded pseudo-random (or strong 488 random) source. See [RFC4086] for advice on generating security- 489 sensitive random data. 491 Source-EID-AFI: This is the address family of the 'Source EID 492 Address' field. 494 Source EID Address: This is the EID of the source host that 495 originated the packet that caused the Map-Request. When Map- 496 Requests are used for refreshing a Map-Cache entry or for RLOC- 497 Probing, an AFI value 0 is used and this field is of zero length. 499 ITR-RLOC-AFI: This is the address family of the 'ITR-RLOC Address' 500 field that follows this field. 502 ITR-RLOC Address: This is used to give the ETR the option of 503 selecting the destination address from any address family for the 504 Map-Reply message. This address MUST be a routable RLOC address 505 of the sender of the Map-Request message. 507 EID mask-len: This is the mask length for the EID-Prefix. 509 EID-Prefix-AFI: This is the address family of the EID-Prefix 510 according to [AFI] and [RFC8060]. 512 EID-Prefix: This prefix is 4 octets for an IPv4 address family and 513 16 octets for an IPv6 address family when the EID-Prefix-AFI is 1 514 or 2, respectively. For other AFIs [AFI], the length varies and 515 for the LCAF AFI the format is defined in [RFC8060]. When a Map- 516 Request is sent by an ITR because a data packet is received for a 517 destination where there is no mapping entry, the EID-Prefix is set 518 to the destination IP address of the data packet, and the 'EID 519 mask-len' is set to 32 or 128 for IPv4 or IPv6, respectively. 520 When an xTR wants to query a site about the status of a mapping it 521 already has cached, the EID-Prefix used in the Map-Request has the 522 same mask length as the EID-Prefix returned from the site when it 523 sent a Map-Reply message. 525 Map-Reply Record: When the M-bit is set, this field is the size of a 526 single "Record" in the Map-Reply format. This Map-Reply record 527 contains the EID-to-RLOC mapping entry associated with the Source 528 EID. This allows the ETR that will receive this Map-Request to 529 cache the data if it chooses to do so. 531 5.3. EID-to-RLOC UDP Map-Request Message 533 A Map-Request is sent from an ITR when it needs a mapping for an EID, 534 wants to test an RLOC for reachability, or wants to refresh a mapping 535 before TTL expiration. For the initial case, the destination IP 536 address used for the Map-Request is the data packet's destination 537 address (i.e., the destination EID) that had a mapping cache lookup 538 failure. For the latter two cases, the destination IP address used 539 for the Map-Request is one of the RLOC addresses from the Locator-Set 540 of the Map-Cache entry. The source address is either an IPv4 or IPv6 541 RLOC address, depending on whether the Map-Request is using an IPv4 542 or IPv6 header, respectively. In all cases, the UDP source port 543 number for the Map-Request message is a 16-bit value selected by the 544 ITR/PITR, and the UDP destination port number is set to the well- 545 known destination port number 4342. A successful Map-Reply, which is 546 one that has a nonce that matches an outstanding Map-Request nonce, 547 will update the cached set of RLOCs associated with the EID-Prefix 548 range. 550 One or more Map-Request ('ITR-RLOC-AFI', 'ITR-RLOC-Address') fields 551 MUST be filled in by the ITR. The number of fields (minus 1) encoded 552 MUST be placed in the 'IRC' field. The ITR MAY include all locally 553 configured Locators in this list or just provide one locator address 554 from each address family it supports. If the ITR erroneously 555 provides no ITR-RLOC addresses, the Map-Replier MUST drop the Map- 556 Request. 558 Map-Requests can also be LISP encapsulated using UDP destination 559 port 4342 with a LISP Type value set to "Encapsulated Control 560 Message", when sent from an ITR to a Map-Resolver. Likewise, Map- 561 Requests are LISP encapsulated the same way from a Map-Server to an 562 ETR. Details on Encapsulated Map-Requests and Map-Resolvers can be 563 found in Section 5.8. 565 Map-Requests MUST be rate-limited. It is RECOMMENDED that a Map- 566 Request for the same EID-Prefix be sent no more than once per second. 568 An ITR that is configured with mapping database information (i.e., it 569 is also an ETR) MAY optionally include those mappings in a Map- 570 Request. When an ETR configured to accept and verify such 571 "piggybacked" mapping data receives such a Map-Request and it does 572 not have this mapping in the map-cache, it MAY originate a "verifying 573 Map-Request", addressed to the map-requesting ITR and the ETR MAY add 574 a Map-Cache entry. If the ETR has a Map-Cache entry that matches the 575 "piggybacked" EID and the RLOC is in the Locator-Set for the entry, 576 then it MAY send the "verifying Map-Request" directly to the 577 originating Map-Request source. If the RLOC is not in the Locator- 578 Set, then the ETR MUST send the "verifying Map-Request" to the 579 "piggybacked" EID. Doing this forces the "verifying Map-Request" to 580 go through the mapping database system to reach the authoritative 581 source of information about that EID, guarding against RLOC-spoofing 582 in the "piggybacked" mapping data. 584 5.4. Map-Reply Message Format 586 0 1 2 3 587 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 589 |Type=2 |P|E|S| Reserved | Record Count | 590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 591 | Nonce . . . | 592 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 593 | . . . Nonce | 594 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 595 | | Record TTL | 596 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 597 R | Locator Count | EID mask-len | ACT |A| Reserved | 598 e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 c | Rsvd | Map-Version Number | EID-Prefix-AFI | 600 o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 r | EID-Prefix | 602 d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 603 | /| Priority | Weight | M Priority | M Weight | 604 | L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 605 | o | Unused Flags |L|p|R| Loc-AFI | 606 | c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 607 | \| Locator | 608 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 610 Packet field descriptions: 612 Type: 2 (Map-Reply) 614 P: This is the probe-bit, which indicates that the Map-Reply is in 615 response to a Locator reachability probe Map-Request. The 'Nonce' 616 field MUST contain a copy of the nonce value from the original 617 Map-Request. See RLOC-probing [I-D.ietf-lisp-rfc6830bis] for more 618 details. 620 E: This bit indicates that the ETR that sends this Map-Reply message 621 is advertising that the site is enabled for the Echo-Nonce Locator 622 reachability algorithm. See Echo-Nonce [I-D.ietf-lisp-rfc6830bis] 623 for more details. 625 S: This is the Security bit. When set to 1, the following 626 authentication information will be appended to the end of the Map- 627 Reply. The details of signing a Map-Reply message can be found in 628 [I-D.ietf-lisp-sec]. 630 0 1 2 3 631 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 633 | AD Type | Authentication Data Content . . . | 634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 636 Reserved: This field MUST be set to 0 on transmit and MUST be 637 ignored on receipt. 639 Record Count: This is the number of records in this reply message. 640 A record is comprised of that portion of the packet labeled 641 'Record' above and occurs the number of times equal to Record 642 Count. 644 Nonce: This is a 24-bit value set in a Data-Probe packet, or a 645 64-bit value from the Map-Request is echoed in this 'Nonce' field 646 of the Map-Reply. When a 24-bit value is supplied, it resides in 647 the low-order 64 bits of the 'Nonce' field. 649 Record TTL: This is the time in minutes the recipient of the Map- 650 Reply will store the mapping. If the TTL is 0, the entry SHOULD 651 be removed from the cache immediately. If the value is 652 0xffffffff, the recipient can decide locally how long to store the 653 mapping. 655 Locator Count: This is the number of Locator entries. A Locator 656 entry comprises what is labeled above as 'Loc'. The Locator count 657 can be 0, indicating that there are no Locators for the EID- 658 Prefix. 660 EID mask-len: This is the mask length for the EID-Prefix. 662 ACT: This 3-bit field describes Negative Map-Reply actions. In any 663 other message type, these bits are set to 0 and ignored on 664 receipt. These bits are used only when the 'Locator Count' field 665 is set to 0. The action bits are encoded only in Map-Reply 666 messages. The actions defined are used by an ITR or PITR when a 667 destination EID matches a negative Map-Cache entry. Unassigned 668 values SHOULD cause a Map-Cache entry to be created, and when 669 packets match this negative cache entry, they will be dropped. 670 The current assigned values are: 672 (0) No-Action: The map-cache is kept alive, and no packet 673 encapsulation occurs. 675 (1) Natively-Forward: The packet is not encapsulated or dropped 676 but natively forwarded. 678 (2) Send-Map-Request: The packet invokes sending a Map-Request. 680 (3) Drop/No-Reason: A packet that matches this map-cache entry is 681 dropped. An ICMP Destination Unreachable message SHOULD be 682 sent. 684 (4) Drop/Policy-Denied: A packet that matches this map-cache 685 entry is dropped. The reason for the Drop action is that a 686 Map-Request for the target-EID is being policy denied by 687 either an xTR or the mapping system. 689 (5) Drop/Authentication-Failure: A packet that matches this map- 690 cache entry is dropped. The reason for the Drop action is 691 that a Map-Request for the target-EID fails an authentication 692 verification-check by either an xTR or the mapping system. 694 A: The Authoritative bit, when sent, is always set to 1 by an ETR. 695 When a Map-Server is proxy Map-Replying for a LISP site, the 696 Authoritative bit is set to 0. This indicates to requesting ITRs 697 that the Map-Reply was not originated by a LISP node managed at 698 the site that owns the EID-Prefix. 700 Map-Version Number: When this 12-bit value is non-zero, the Map- 701 Reply sender is informing the ITR what the version number is for 702 the EID record contained in the Map-Reply. The ETR can allocate 703 this number internally but MUST coordinate this value with other 704 ETRs for the site. When this value is 0, there is no versioning 705 information conveyed. The Map-Version Number can be included in 706 Map-Request and Map-Register messages. See Map-Versioning 707 [I-D.ietf-lisp-rfc6830bis] for more details. 709 EID-Prefix-AFI: Address family of the EID-Prefix according to [AFI] 710 and [RFC8060]. 712 EID-Prefix: This prefix is 4 octets for an IPv4 address family and 713 16 octets for an IPv6 address family. 715 Priority: Each RLOC is assigned a unicast Priority. Lower values 716 are more preferable. When multiple RLOCs have the same Priority, 717 they MAY be used in a load-split fashion. A value of 255 means 718 the RLOC MUST NOT be used for unicast forwarding. 720 Weight: When priorities are the same for multiple RLOCs, the Weight 721 indicates how to balance unicast traffic between them. Weight is 722 encoded as a relative weight of total unicast packets that match 723 the mapping entry. For example, if there are 4 Locators in a 724 Locator-Set, where the Weights assigned are 30, 20, 20, and 10, 725 the first Locator will get 37.5% of the traffic, the 2nd and 3rd 726 Locators will get 25% of the traffic, and the 4th Locator will get 727 12.5% of the traffic. If all Weights for a Locator-Set are equal, 728 the receiver of the Map-Reply will decide how to load-split the 729 traffic. See RLOC-hashing [I-D.ietf-lisp-rfc6830bis] for a 730 suggested hash algorithm to distribute the load across Locators 731 with the same Priority and equal Weight values. 733 M Priority: Each RLOC is assigned a multicast Priority used by an 734 ETR in a receiver multicast site to select an ITR in a source 735 multicast site for building multicast distribution trees. A value 736 of 255 means the RLOC MUST NOT be used for joining a multicast 737 distribution tree. For more details, see [RFC6831]. 739 M Weight: When priorities are the same for multiple RLOCs, the 740 Weight indicates how to balance building multicast distribution 741 trees across multiple ITRs. The Weight is encoded as a relative 742 weight (similar to the unicast Weights) of the total number of 743 trees built to the source site identified by the EID-Prefix. If 744 all Weights for a Locator-Set are equal, the receiver of the Map- 745 Reply will decide how to distribute multicast state across ITRs. 746 For more details, see [RFC6831]. 748 Unused Flags: These are set to 0 when sending and ignored on 749 receipt. 751 L: When this bit is set, the Locator is flagged as a local Locator to 752 the ETR that is sending the Map-Reply. When a Map-Server is doing 753 proxy Map-Replying for a LISP site, the L-bit is set to 0 for all 754 Locators in this Locator-Set. 756 p: When this bit is set, an ETR informs the RLOC-Probing ITR that the 757 locator address for which this bit is set is the one being RLOC- 758 probed and MAY be different from the source address of the Map- 759 Reply. An ITR that RLOC-probes a particular Locator MUST use this 760 Locator for retrieving the data structure used to store the fact 761 that the Locator is reachable. The p-bit is set for a single 762 Locator in the same Locator-Set. If an implementation sets more 763 than one p-bit erroneously, the receiver of the Map-Reply MUST 764 select the first Locator. The p-bit MUST NOT be set for Locator- 765 Set records sent in Map-Request and Map-Register messages. 767 R: This is set when the sender of a Map-Reply has a route to the 768 Locator in the Locator data record. This receiver MAY find this 769 useful to know if the Locator is up but not necessarily reachable 770 from the receiver's point of view. See also EID-Reachability 771 [I-D.ietf-lisp-rfc6830bis] for another way the R-bit MAY be used. 773 Locator: This is an IPv4 or IPv6 address (as encoded by the 'Loc- 774 AFI' field) assigned to an ETR. Note that the destination RLOC 775 address MAY be an anycast address. A source RLOC can be an 776 anycast address as well. The source or destination RLOC MUST NOT 777 be the broadcast address (255.255.255.255 or any subnet broadcast 778 address known to the router) and MUST NOT be a link-local 779 multicast address. The source RLOC MUST NOT be a multicast 780 address. The destination RLOC SHOULD be a multicast address if it 781 is being mapped from a multicast destination EID. 783 5.5. EID-to-RLOC UDP Map-Reply Message 785 A Map-Reply returns an EID-Prefix with a prefix length that is less 786 than or equal to the EID being requested. The EID being requested is 787 either from the destination field of an IP header of a Data-Probe or 788 the EID record of a Map-Request. The RLOCs in the Map-Reply are 789 routable IP addresses of all ETRs for the LISP site. Each RLOC 790 conveys status reachability but does not convey path reachability 791 from a requester's perspective. Separate testing of path 792 reachability is required. See RLOC-reachability 793 [I-D.ietf-lisp-rfc6830bis] for details. 795 Note that a Map-Reply MAY contain different EID-Prefix granularity 796 (prefix + length) than the Map-Request that triggers it. This might 797 occur if a Map-Request were for a prefix that had been returned by an 798 earlier Map-Reply. In such a case, the requester updates its cache 799 with the new prefix information and granularity. For example, a 800 requester with two cached EID-Prefixes that are covered by a Map- 801 Reply containing one less-specific prefix replaces the entry with the 802 less-specific EID-Prefix. Note that the reverse, replacement of one 803 less-specific prefix with multiple more-specific prefixes, can also 804 occur, not by removing the less-specific prefix but rather by adding 805 the more-specific prefixes that, during a lookup, will override the 806 less-specific prefix. 808 When an EID moves out of a LISP site [I-D.ietf-lisp-eid-mobility], 809 the database mapping system may have overlapping EID-prefixes. Or 810 when a LISP site is configured with multiple sets of ETRs that 811 support different EID-prefix lengths, the database mapping system may 812 have overlapping EID-prefixes. When overlapping EID-prefixes exist, 813 a Map-Request with an EID that best matches any EID-Prefix MUST be 814 returned in a single Map-Reply message. For instance, if an ETR had 815 database mapping entries for EID-Prefixes: 817 10.0.0.0/8 818 10.1.0.0/16 819 10.1.1.0/24 820 10.1.2.0/24 822 A Map-Request for EID 10.1.1.1 would cause a Map-Reply with a record 823 count of 1 to be returned with a mapping record EID-Prefix of 824 10.1.1.0/24. 826 A Map-Request for EID 10.1.5.5 would cause a Map-Reply with a record 827 count of 3 to be returned with mapping records for EID-Prefixes 828 10.1.0.0/16, 10.1.1.0/24, and 10.1.2.0/24. 830 Note that not all overlapping EID-Prefixes need to be returned but 831 only the more-specific entries (note that in the second example above 832 10.0.0.0/8 was not returned for requesting EID 10.1.5.5) for the 833 matching EID-Prefix of the requesting EID. When more than one EID- 834 Prefix is returned, all SHOULD use the same Time to Live value so 835 they can all time out at the same time. When a more-specific EID- 836 Prefix is received later, its Time to Live value in the Map-Reply 837 record can be stored even when other less-specific entries exist. 838 When a less-specific EID-Prefix is received later, its map-cache 839 expiration time SHOULD be set to the minimum expiration time of any 840 more-specific EID-Prefix in the map-cache. This is done so the 841 integrity of the EID-Prefix set is wholly maintained and so no more- 842 specific entries are removed from the map-cache while keeping less- 843 specific entries. 845 Map-Replies SHOULD be sent for an EID-Prefix no more often than once 846 per second to the same requesting router. For scalability, it is 847 expected that aggregation of EID addresses into EID-Prefixes will 848 allow one Map-Reply to satisfy a mapping for the EID addresses in the 849 prefix range, thereby reducing the number of Map-Request messages. 851 Map-Reply records can have an empty Locator-Set. A Negative Map- 852 Reply is a Map-Reply with an empty Locator-Set. Negative Map-Replies 853 convey special actions by the sender to the ITR or PITR that have 854 solicited the Map-Reply. There are two primary applications for 855 Negative Map-Replies. The first is for a Map-Resolver to instruct an 856 ITR or PITR when a destination is for a LISP site versus a non-LISP 857 site, and the other is to source quench Map-Requests that are sent 858 for non-allocated EIDs. 860 For each Map-Reply record, the list of Locators in a Locator-Set MUST 861 appear in the same order for each ETR that originates a Map-Reply 862 message. The Locator-Set MUST be sorted in order of ascending IP 863 address where an IPv4 locator address is considered numerically 'less 864 than' an IPv6 locator address. 866 When sending a Map-Reply message, the destination address is copied 867 from one of the 'ITR-RLOC' fields from the Map-Request. The ETR can 868 choose a locator address from one of the address families it 869 supports. For Data-Probes, the destination address of the Map-Reply 870 is copied from the source address of the Data-Probe message that is 871 invoking the reply. The source address of the Map-Reply is one of 872 the local IP addresses chosen to allow Unicast Reverse Path 873 Forwarding (uRPF) checks to succeed in the upstream service provider. 874 The destination port of a Map-Reply message is copied from the source 875 port of the Map-Request or Data-Probe, and the source port of the 876 Map-Reply message is set to the well-known UDP port 4342. 878 5.6. Map-Register Message Format 880 This section specifies the encoding format for the Map-Register 881 message. The message is sent in UDP with a destination UDP port of 882 4342 and a randomly selected UDP source port number. 884 The Map-Register message format is: 886 0 1 2 3 887 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 888 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 889 |Type=3 |P|S|I| Reserved |E|T|a|m|M| Record Count | 890 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 891 | Nonce . . . | 892 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 893 | . . . Nonce | 894 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 895 | Key ID | Algorithm ID | Authentication Data Length | 896 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 897 ~ Authentication Data ~ 898 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 899 | | Record TTL | 900 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 901 R | Locator Count | EID mask-len | ACT |A| Reserved | 902 e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 903 c | Rsvd | Map-Version Number | EID-Prefix-AFI | 904 o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 905 r | EID-Prefix | 906 d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 907 | /| Priority | Weight | M Priority | M Weight | 908 | L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 909 | o | Unused Flags |L|p|R| Loc-AFI | 910 | c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 911 | \| Locator | 912 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 914 Packet field descriptions: 916 Type: 3 (Map-Register) 918 P: This is the proxy Map-Reply bit. When set to 1, an ETR sends a 919 Map-Register message requesting the Map-Server to proxy a Map- 920 Reply. The Map-Server will send non-authoritative Map-Replies on 921 behalf of the ETR. 923 S: This is the security-capable bit. When set, the procedures from 924 [I-D.ietf-lisp-sec] are supported. 926 I: This is the xTR-ID bit. When this bit is set, what is appended to 927 the Map-Register is a 128-bit xTR router-ID and then a 64-bit 928 site-ID. See LISP NAT-Traversal procedures in 929 [I-D.ermagan-lisp-nat-traversal] for details. 931 Reserved: This field MUST be set to 0 on transmit and MUST be 932 ignored on receipt. 934 E: This is the Map-Register EID-notify bit. This is used by a First- 935 Hop-Router (FHR) which discovers a dynamic-EID. This EID-notify 936 based Map-Register is sent by the FHR to the same site xTR that 937 propogates the Map-Register to the mapping system. The site xTR 938 keeps state to later Map-Notify the FHR after the EID has moves 939 away. See [I-D.ietf-lisp-eid-mobility] for a detailed use-case. 941 T: This is the use-TTL for timeout bit. When set to 1, the xTR wants 942 the Map-Server to time out registrations based on the value in the 943 "Record TTL" field of this message. 945 a: This is the merge-request bit. When set to 1, the xTR requests to 946 merge RLOC-records from different xTRs registering the same EID- 947 record. See signal-free multicast 948 [I-D.ietf-lisp-signal-free-multicast] for one use case example. 950 m: This is the mobile-node bit. When set to 1, the registering xTR 951 supports the procedures in [I-D.ietf-lisp-mn]. 953 M: This is the want-map-notify bit. When set to 1, an ETR is 954 requesting a Map-Notify message to be returned in response to 955 sending a Map-Register message. The Map-Notify message sent by a 956 Map-Server is used to acknowledge receipt of a Map-Register 957 message. 959 Record Count: This is the number of records in this Map-Register 960 message. A record is comprised of that portion of the packet 961 labeled 'Record' above and occurs the number of times equal to 962 Record Count. 964 Nonce: This 8-octet 'Nonce' field is set to 0 in Map-Register 965 messages if no Map-Notify message is expected to acknowledge it. 966 Since the Map-Register message is authenticated, the 'Nonce' field 967 is not currently used for any security function but MAY be in the 968 future as part of an anti-replay solution. 970 Key ID: This is a configured key-id value that corresponds to a 971 shared-secret password that is used to authenticate the sender. 972 Multiple shared-secrets can be used to roll over keys in a non- 973 disruptive way. 975 Algorithm ID: This is the configured Message Authentication Code 976 (MAC) algorithm value used for the authentication function. See 977 Algorithm ID Numbers in the Section 8.3 for codepoint assignments. 979 Authentication Data Length: This is the length in octets of the 980 'Authentication Data' field that follows this field. The length 981 of the 'Authentication Data' field is dependent on the MAC 982 algorithm used. The length field allows a device that doesn't 983 know the MAC algorithm to correctly parse the packet. 985 Authentication Data: This is the message digest used from the output 986 of the MAC algorithm. The entire Map-Register payload is 987 authenticated with this field preset to 0. After the MAC is 988 computed, it is placed in this field. Implementations of this 989 specification MUST include support for HMAC-SHA-1-96 [RFC2404], 990 and support for HMAC-SHA-256-128 [RFC4868] is RECOMMENDED. 992 The definition of the rest of the Map-Register can be found in 993 Section 5.4. 995 5.7. Map-Notify/Map-Notify-Ack Message Format 997 This section specifies the encoding format for the Map-Notify and 998 Map-Notify-Ack messages. The messages are sent inside a UDP packet 999 with source and destination UDP ports equal to 4342. 1001 The Map-Notify and Map-Notify-Ack message formats are: 1003 0 1 2 3 1004 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1005 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1006 |Type=4/5| Reserved | Record Count | 1007 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1008 | Nonce . . . | 1009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1010 | . . . Nonce | 1011 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1012 | Key ID | Algorithm ID | Authentication Data Length | 1013 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1014 ~ Authentication Data ~ 1015 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1016 | | Record TTL | 1017 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1018 R | Locator Count | EID mask-len | ACT |A| Reserved | 1019 e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1020 c | Rsvd | Map-Version Number | EID-Prefix-AFI | 1021 o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1022 r | EID-Prefix | 1023 d +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1024 | /| Priority | Weight | M Priority | M Weight | 1025 | L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1026 | o | Unused Flags |L|p|R| Loc-AFI | 1027 | c +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1028 | \| Locator | 1029 +-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1031 Packet field descriptions: 1033 Type: 4/5 (Map-Notify/Map-Notify-Ack) 1035 The Map-Notify message has the same contents as a Map-Register 1036 message. See the Map-Register section for field descriptions. 1038 The Map-Notify-Ack message has the same contents as a Map-Notify 1039 message. It is used to acknowledge the receipt of a Map-Notify and 1040 for the sender to stop retransmitting a Map-Notify with the same 1041 nonce. 1043 5.8. Encapsulated Control Message Format 1045 An Encapsulated Control Message (ECM) is used to encapsulate control 1046 packets sent between xTRs and the mapping database system. 1048 0 1 2 3 1049 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1050 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1051 / | IPv4 or IPv6 Header | 1052 OH | (uses RLOC addresses) | 1053 \ | | 1054 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1055 / | Source Port = xxxx | Dest Port = 4342 | 1056 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1057 \ | UDP Length | UDP Checksum | 1058 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1059 LH |Type=8 |S|D|E|M| Reserved | 1060 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1061 / | IPv4 or IPv6 Header | 1062 IH | (uses RLOC or EID addresses) | 1063 \ | | 1064 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1065 / | Source Port = xxxx | Dest Port = yyyy | 1066 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1067 \ | UDP Length | UDP Checksum | 1068 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1069 LCM | LISP Control Message | 1070 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1072 Packet header descriptions: 1074 OH: The outer IPv4 or IPv6 header, which uses RLOC addresses in the 1075 source and destination header address fields. 1077 UDP: The outer UDP header with destination port 4342. The source 1078 port is randomly allocated. The checksum field MUST be non- 1079 zero. 1081 LH: Type 8 is defined to be a "LISP Encapsulated Control Message", 1082 and what follows is either an IPv4 or IPv6 header as encoded by 1083 the first 4 bits after the 'Reserved' field. 1085 Type: 8 (Encapsulated Control Message (ECM)) 1087 S: This is the Security bit. When set to 1, the procedures from 1088 [I-D.ietf-lisp-sec] are followed. 1090 D: This is the DDT-bit. When set to 1, the sender is requesting a 1091 Map-Referral message to be returned. The details of this 1092 procedure are described in [RFC8111]. 1094 E: This is the to-ETR bit. When set to 1, the Map-Server's 1095 intention is to forward the ECM to an authoritative ETR. 1097 M: This is the to-MS bit. When set to 1, a Map-Request is being 1098 sent to a co-located Map-Resolver and Map-Server where the 1099 message can be processed directly by the Map-Server versus the 1100 Map-Resolver using the LISP-DDT procedures in [RFC8111]. 1102 0 1 2 3 1103 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1104 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1105 | AD Type | Authentication Data Content . . . | 1106 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1108 IH: The inner IPv4 or IPv6 header, which can use either RLOC or EID 1109 addresses in the header address fields. When a Map-Request is 1110 encapsulated in this packet format, the destination address in 1111 this header is an EID. 1113 UDP: The inner UDP header, where the port assignments depend on the 1114 control packet being encapsulated. When the control packet is 1115 a Map-Request or Map-Register, the source port is selected by 1116 the ITR/PITR and the destination port is 4342. When the 1117 control packet is a Map-Reply, the source port is 4342 and the 1118 destination port is assigned from the source port of the 1119 invoking Map-Request. Port number 4341 MUST NOT be assigned to 1120 either port. The checksum field MUST be non-zero. 1122 LCM: The format is one of the control message formats described in 1123 this section. At this time, only Map-Request messages are 1124 allowed to be control-plane (ECM) encapsulated. In the future, 1125 PIM Join/Prune messages [RFC6831] might be allowed. 1126 Encapsulating other types of LISP control messages is for 1127 further study. When Map-Requests are sent for RLOC-Probing 1128 purposes (i.e., the probe-bit is set), they MUST NOT be sent 1129 inside Encapsulated Control Messages. 1131 6. Interactions with Other LISP Components 1133 6.1. ITR EID-to-RLOC Mapping Resolution 1135 An ITR is configured with one or more Map-Resolver addresses. These 1136 addresses are "Locators" (or RLOCs) and MUST be routable on the 1137 underlying core network; they MUST NOT need to be resolved through 1138 LISP EID-to-RLOC mapping, as that would introduce a circular 1139 dependency. When using a Map-Resolver, an ITR does not need to 1140 connect to any other database mapping system. In particular, the ITR 1141 need not connect to the LISP+ALT infrastructure or implement the BGP 1142 and GRE protocols that it uses. 1144 An ITR sends an Encapsulated Map-Request to a configured Map-Resolver 1145 when it needs an EID-to-RLOC mapping that is not found in its local 1146 map-cache. Using the Map-Resolver greatly reduces both the 1147 complexity of the ITR implementation and the costs associated with 1148 its operation. 1150 In response to an Encapsulated Map-Request, the ITR can expect one of 1151 the following: 1153 o An immediate Negative Map-Reply (with action code of "Natively- 1154 Forward", 15-minute Time to Live (TTL)) from the Map-Resolver if 1155 the Map-Resolver can determine that the requested EID does not 1156 exist. The ITR saves the EID-Prefix returned in the Map-Reply in 1157 its cache, marks it as non-LISP-capable, and knows not to attempt 1158 LISP encapsulation for destinations matching it. 1160 o A Negative Map-Reply, with action code of "Natively-Forward", from 1161 a Map-Server that is authoritative for an EID-Prefix that matches 1162 the requested EID but that does not have an actively registered, 1163 more-specific ID-prefix. In this case, the requested EID is said 1164 to match a "hole" in the authoritative EID-Prefix. If the 1165 requested EID matches a more-specific EID-Prefix that has been 1166 delegated by the Map-Server but for which no ETRs are currently 1167 registered, a 1-minute TTL is returned. If the requested EID 1168 matches a non-delegated part of the authoritative EID-Prefix, then 1169 it is not a LISP EID and a 15-minute TTL is returned. See 1170 Section 6.2 for discussion of aggregate EID-Prefixes and details 1171 of Map-Server EID-Prefix matching. 1173 o A LISP Map-Reply from the ETR that owns the EID-to-RLOC mapping or 1174 possibly from a Map-Server answering on behalf of the ETR. See 1175 Section 6.4 for more details on Map-Resolver message processing. 1177 Note that an ITR MAY be configured to both use a Map-Resolver and to 1178 participate in a LISP+ALT logical network. In such a situation, the 1179 ITR SHOULD send Map-Requests through the ALT network for any EID- 1180 Prefix learned via ALT BGP. Such a configuration is expected to be 1181 very rare, since there is little benefit to using a Map-Resolver if 1182 an ITR is already using LISP+ALT. There would be, for example, no 1183 need for such an ITR to send a Map-Request to a possibly non-existent 1184 EID (and rely on Negative Map-Replies) if it can consult the ALT 1185 database to verify that an EID-Prefix is present before sending that 1186 Map-Request. 1188 6.2. EID-Prefix Configuration and ETR Registration 1190 An ETR publishes its EID-Prefixes on a Map-Server by sending LISP 1191 Map-Register messages. A Map-Register message includes 1192 authentication data, so prior to sending a Map-Register message, the 1193 ETR and Map-Server SHOULD be configured with a shared secret or other 1194 relevant authentication information. A Map-Server's configuration 1195 SHOULD also include a list of the EID-Prefixes for which each ETR is 1196 authoritative. Upon receipt of a Map-Register from an ETR, a Map- 1197 Server accepts only EID-Prefixes that are configured for that ETR. 1198 Failure to implement such a check would leave the mapping system 1199 vulnerable to trivial EID-Prefix hijacking attacks. As developers 1200 and operators gain experience with the mapping system, additional, 1201 stronger security measures MAY be added to the registration process. 1203 In addition to the set of EID-Prefixes defined for each ETR that MAY 1204 register, a Map-Server is typically also configured with one or more 1205 aggregate prefixes that define the part of the EID numbering space 1206 assigned to it. When LISP+ALT is the database in use, aggregate EID- 1207 Prefixes are implemented as discard routes and advertised into ALT 1208 BGP. The existence of aggregate EID-Prefixes in a Map-Server's 1209 database means that it MAY receive Map Requests for EID-Prefixes that 1210 match an aggregate but do not match a registered prefix; Section 6.3 1211 describes how this is handled. 1213 Map-Register messages are sent periodically from an ETR to a Map- 1214 Server with a suggested interval between messages of one minute. A 1215 Map-Server SHOULD time out and remove an ETR's registration if it has 1216 not received a valid Map-Register message within the past 1217 three minutes. When first contacting a Map-Server after restart or 1218 changes to its EID-to-RLOC database mappings, an ETR MAY initially 1219 send Map-Register messages at an increased frequency, up to one every 1220 20 seconds. This "quick registration" period is limited to 1221 five minutes in duration. 1223 An ETR MAY request that a Map-Server explicitly acknowledge receipt 1224 and processing of a Map-Register message by setting the "want-map- 1225 notify" (M-bit) flag. A Map-Server that receives a Map-Register with 1226 this flag set will respond with a Map-Notify message. Typical use of 1227 this flag by an ETR would be to set it for Map-Register messages sent 1228 during the initial "quick registration" with a Map-Server but then 1229 set it only occasionally during steady-state maintenance of its 1230 association with that Map-Server. Note that the Map-Notify message 1231 is sent to UDP destination port 4342, not to the source port 1232 specified in the original Map-Register message. 1234 Note that a one-minute minimum registration interval during 1235 maintenance of an ETR-Map-Server association places a lower bound on 1236 how quickly and how frequently a mapping database entry can be 1237 updated. This MAY have implications for what sorts of mobility can 1238 be supported directly by the mapping system; shorter registration 1239 intervals or other mechanisms might be needed to support faster 1240 mobility in some cases. For a discussion on one way that faster 1241 mobility MAY be implemented for individual devices, please see 1242 [I-D.ietf-lisp-mn]. 1244 An ETR MAY also request, by setting the "proxy Map-Reply" flag 1245 (P-bit) in the Map-Register message, that a Map-Server answer Map- 1246 Requests instead of forwarding them to the ETR. See 1247 [I-D.ietf-lisp-rfc6830bis] for details on how the Map-Server sets 1248 certain flags (such as those indicating whether the message is 1249 authoritative and how returned Locators SHOULD be treated) when 1250 sending a Map-Reply on behalf of an ETR. When an ETR requests proxy 1251 reply service, it SHOULD include all RLOCs for all ETRs for the EID- 1252 Prefix being registered, along with the routable flag ("R-bit") 1253 setting for each RLOC. The Map-Server includes all of this 1254 information in Map-Reply messages that it sends on behalf of the ETR. 1255 This differs from a non-proxy registration, since the latter need 1256 only provide one or more RLOCs for a Map-Server to use for forwarding 1257 Map-Requests; the registration information is not used in Map- 1258 Replies, so it being incomplete is not incorrect. 1260 An ETR that uses a Map-Server to publish its EID-to-RLOC mappings 1261 does not need to participate further in the mapping database 1262 protocol(s). When using a LISP+ALT mapping database, for example, 1263 this means that the ETR does not need to implement GRE or BGP, which 1264 greatly simplifies its configuration and reduces its cost of 1265 operation. 1267 Note that use of a Map-Server does not preclude an ETR from also 1268 connecting to the mapping database (i.e., it could also connect to 1269 the LISP+ALT network), but doing so doesn't seem particularly useful, 1270 as the whole purpose of using a Map-Server is to avoid the complexity 1271 of the mapping database protocols. 1273 6.3. Map-Server Processing 1275 Once a Map-Server has EID-Prefixes registered by its client ETRs, it 1276 can accept and process Map-Requests for them. 1278 In response to a Map-Request (received over the ALT if LISP+ALT is in 1279 use), the Map-Server first checks to see if the destination EID 1280 matches a configured EID-Prefix. If there is no match, the Map- 1281 Server returns a Negative Map-Reply with action code "Natively- 1282 Forward" and a 15-minute TTL. This MAY occur if a Map Request is 1283 received for a configured aggregate EID-Prefix for which no more- 1284 specific EID-Prefix exists; it indicates the presence of a non-LISP 1285 "hole" in the aggregate EID-Prefix. 1287 Next, the Map-Server checks to see if any ETRs have registered the 1288 matching EID-Prefix. If none are found, then the Map-Server returns 1289 a Negative Map-Reply with action code "Natively-Forward" and a 1290 1-minute TTL. 1292 If any of the registered ETRs for the EID-Prefix have requested proxy 1293 reply service, then the Map-Server answers the request instead of 1294 forwarding it. It returns a Map-Reply with the EID-Prefix, RLOCs, 1295 and other information learned through the registration process. 1297 If none of the ETRs have requested proxy reply service, then the Map- 1298 Server re-encapsulates and forwards the resulting Encapsulated Map- 1299 Request to one of the registered ETRs. It does not otherwise alter 1300 the Map-Request, so any Map-Reply sent by the ETR is returned to the 1301 RLOC in the Map-Request, not to the Map-Server. Unless also acting 1302 as a Map-Resolver, a Map-Server SHOULD never receive Map-Replies; any 1303 such messages SHOULD be discarded without response, perhaps 1304 accompanied by the logging of a diagnostic message if the rate of 1305 Map-Replies is suggestive of malicious traffic. 1307 6.4. Map-Resolver Processing 1309 Upon receipt of an Encapsulated Map-Request, a Map-Resolver 1310 decapsulates the enclosed message and then searches for the requested 1311 EID in its local database of mapping entries (statically configured 1312 or learned from associated ETRs if the Map-Resolver is also a Map- 1313 Server offering proxy reply service). If it finds a matching entry, 1314 it returns a LISP Map-Reply with the known mapping. 1316 If the Map-Resolver does not have the mapping entry and if it can 1317 determine that the EID is not in the mapping database (for example, 1318 if LISP+ALT is used, the Map-Resolver will have an ALT forwarding 1319 table that covers the full EID space), it immediately returns a 1320 negative LISP Map-Reply, with action code "Natively-Forward" and a 1321 15-minute TTL. To minimize the number of negative cache entries 1322 needed by an ITR, the Map-Resolver SHOULD return the least-specific 1323 prefix that both matches the original query and does not match any 1324 EID-Prefix known to exist in the LISP-capable infrastructure. 1326 If the Map-Resolver does not have sufficient information to know 1327 whether the EID exists, it needs to forward the Map-Request to 1328 another device that has more information about the EID being 1329 requested. To do this, it forwards the unencapsulated Map-Request, 1330 with the original ITR RLOC as the source, to the mapping database 1331 system. Using LISP+ALT, the Map-Resolver is connected to the ALT 1332 network and sends the Map-Request to the next ALT hop learned from 1333 its ALT BGP neighbors. The Map-Resolver does not send any response 1334 to the ITR; since the source RLOC is that of the ITR, the ETR or Map- 1335 Server that receives the Map-Request over the ALT and responds will 1336 do so directly to the ITR. 1338 6.4.1. Anycast Map-Resolver Operation 1340 A Map-Resolver can be set up to use "anycast", where the same address 1341 is assigned to multiple Map-Resolvers and is propagated through IGP 1342 routing, to facilitate the use of a topologically close Map-Resolver 1343 by each ITR. 1345 Note that Map-Server associations with ETRs SHOULD NOT use anycast 1346 addresses, as registrations need to be established between an ETR and 1347 a specific set of Map-Servers, each identified by a specific 1348 registration association. 1350 7. Security Considerations 1352 The 2-way LISP header nonce exchange documented in 1353 [I-D.ietf-lisp-rfc6830bis] can be used to avoid ITR spoofing attacks. 1355 To publish an authoritative EID-to-RLOC mapping with a Map-Server, an 1356 ETR includes authentication data that is a hash of the message using 1357 a pair-wise shared key. An implementation MUST support use of HMAC- 1358 SHA-1-96 [RFC2104] and SHOULD support use of HMAC-SHA-256-128 1359 [RFC6234] (SHA-256 truncated to 128 bits). 1361 As noted in Section 6.2, a Map-Server SHOULD verify that all EID- 1362 Prefixes registered by an ETR match the configuration stored on the 1363 Map-Server. 1365 The currently defined authentication mechanism for Map-Register 1366 messages does not provide protection against "replay" attacks by a 1367 "man-in-the-middle". Additional work is needed in this area. 1369 [I-D.ietf-lisp-sec] defines a proposed mechanism for providing origin 1370 authentication, integrity, anti-replay protection, and prevention of 1371 man-in-the-middle and "overclaiming" attacks on the Map-Request/Map- 1372 Reply exchange. Work is ongoing on this and other proposals for 1373 resolving these open security issues. 1375 While beyond the scope of securing an individual Map-Server or Map- 1376 Resolver, it SHOULD be noted that a BGP-based LISP+ALT network (if 1377 ALT is used as the mapping database infrastructure) can take 1378 advantage of standards work on adding security to BGP. 1380 A complete LISP threat analysis has been published in [RFC7835]. 1381 Please refer to it for more security related details. 1383 8. IANA Considerations 1385 This section provides guidance to the Internet Assigned Numbers 1386 Authority (IANA) regarding registration of values related to this 1387 LISP control-plane specification, in accordance with BCP 26 1388 [RFC8126]. 1390 There are three namespaces (listed in the sub-sections below) in LISP 1391 that have been registered. 1393 o LISP IANA registry allocations SHOULD NOT be made for purposes 1394 unrelated to LISP routing or transport protocols. 1396 o The following policies are used here with the meanings defined in 1397 BCP 26: "Specification Required", "IETF Review", "Experimental 1398 Use", and "First Come First Served". 1400 8.1. LISP Packet Type Codes 1402 It is being requested that the IANA be authoritative for LISP Packet 1403 Type definitions and that it refers to this document as well as 1404 [RFC8113] as references. 1406 Based on deployment experience of [RFC6830], the Map-Notify-Ack 1407 message, message type 5, was added to this document. This document 1408 requests IANA to add it to the LISP Packet Type Registry. 1410 8.2. LISP ACT and Flag Fields 1412 New ACT values can be allocated through IETF review or IESG approval. 1413 Four values have already been allocated by [RFC6830]. This 1414 specification changes the name of ACT type 3 value from "Drop" to 1415 "Drop/No-Reason" as well as adding two new ACT values, the "Drop/ 1416 Policy-Denied" (type 4) and "Drop/Authentication-Failure" (type 5). 1418 In addition, LISP has a number of flag fields and reserved fields, 1419 such as the LISP header flags field [I-D.ietf-lisp-rfc6830bis]. New 1420 bits for flags in these fields can be implemented after IETF review 1421 or IESG approval, but these need not be managed by IANA. 1423 8.3. LISP Address Type Codes 1425 LISP Canonical Address Format (LCAF) [RFC8060] is an 8-bit field that 1426 defines LISP-specific encodings for AFI value 16387. LCAF encodings 1427 are used for specific use-cases where different address types for 1428 EID-records and RLOC-records are required. 1430 The IANA registry "LISP Canonical Address Format (LCAF) Types" is 1431 used for LCAF types, the registry for LCAF types use the 1432 Specification Required policy [RFC8126]. Initial values for the 1433 registry as well as further information can be found in [RFC8060]. 1435 Therefore, there is no longer a need for the "LISP Address Type 1436 Codes" registry requested by [RFC6830]. This document requests to 1437 remove it. 1439 8.4. LISP Algorithm ID Numbers 1441 In [RFC6830], a request for a "LISP Key ID Numbers" registry was 1442 submitted. This document renames the registry to "LISP Algorithm ID 1443 Numbers" and requests the IANA to make the name change. 1445 The following Algorithm ID values are defined by this specification 1446 as used in any packet type that references a 'Algorithm ID' field: 1448 Name Number Defined in 1449 ----------------------------------------------- 1450 None 0 n/a 1451 HMAC-SHA-1-96 1 [RFC2404] 1452 HMAC-SHA-256-128 2 [RFC4868] 1454 Number values are in the range of 0 to 255. The allocation of values 1455 is on a first come first served basis. 1457 9. References 1459 9.1. Normative References 1461 [RFC1035] Mockapetris, P., "Domain names - implementation and 1462 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1463 November 1987, . 1465 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1466 Requirement Levels", BCP 14, RFC 2119, 1467 DOI 10.17487/RFC2119, March 1997, 1468 . 1470 [RFC2404] Madson, C. and R. Glenn, "The Use of HMAC-SHA-1-96 within 1471 ESP and AH", RFC 2404, DOI 10.17487/RFC2404, November 1472 1998, . 1474 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 1475 "Randomness Requirements for Security", BCP 106, RFC 4086, 1476 DOI 10.17487/RFC4086, June 2005, 1477 . 1479 [RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA- 1480 384, and HMAC-SHA-512 with IPsec", RFC 4868, 1481 DOI 10.17487/RFC4868, May 2007, 1482 . 1484 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 1485 Locator/ID Separation Protocol (LISP)", RFC 6830, 1486 DOI 10.17487/RFC6830, January 2013, 1487 . 1489 [RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The 1490 Locator/ID Separation Protocol (LISP) for Multicast 1491 Environments", RFC 6831, DOI 10.17487/RFC6831, January 1492 2013, . 1494 [RFC6836] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, 1495 "Locator/ID Separation Protocol Alternative Logical 1496 Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836, 1497 January 2013, . 1499 [RFC6837] Lear, E., "NERD: A Not-so-novel Endpoint ID (EID) to 1500 Routing Locator (RLOC) Database", RFC 6837, 1501 DOI 10.17487/RFC6837, January 2013, 1502 . 1504 [RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical 1505 Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060, 1506 February 2017, . 1508 [RFC8111] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. 1509 Smirnov, "Locator/ID Separation Protocol Delegated 1510 Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111, 1511 May 2017, . 1513 [RFC8113] Boucadair, M. and C. Jacquenet, "Locator/ID Separation 1514 Protocol (LISP): Shared Extension Message & IANA Registry 1515 for Packet Type Allocations", RFC 8113, 1516 DOI 10.17487/RFC8113, March 2017, 1517 . 1519 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1520 Writing an IANA Considerations Section in RFCs", BCP 26, 1521 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1522 . 1524 9.2. Informative References 1526 [AFI] IANA, "Address Family Identifier (AFIs)", ADDRESS FAMILY 1527 NUMBERS http://www.iana.org/assignments/address-family- 1528 numbers/address-family-numbers.xhtml?, Febuary 2007. 1530 [I-D.ermagan-lisp-nat-traversal] 1531 Ermagan, V., Farinacci, D., Lewis, D., Skriver, J., Maino, 1532 F., and C. White, "NAT traversal for LISP", draft-ermagan- 1533 lisp-nat-traversal-13 (work in progress), September 2017. 1535 [I-D.ietf-lisp-eid-mobility] 1536 Portoles-Comeras, M., Ashtaputre, V., Moreno, V., Maino, 1537 F., and D. Farinacci, "LISP L2/L3 EID Mobility Using a 1538 Unified Control Plane", draft-ietf-lisp-eid-mobility-01 1539 (work in progress), November 2017. 1541 [I-D.ietf-lisp-introduction] 1542 Cabellos-Aparicio, A. and D. Saucez, "An Architectural 1543 Introduction to the Locator/ID Separation Protocol 1544 (LISP)", draft-ietf-lisp-introduction-13 (work in 1545 progress), April 2015. 1547 [I-D.ietf-lisp-mn] 1548 Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP 1549 Mobile Node", draft-ietf-lisp-mn-01 (work in progress), 1550 October 2017. 1552 [I-D.ietf-lisp-rfc6830bis] 1553 Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A. 1554 Cabellos-Aparicio, "The Locator/ID Separation Protocol 1555 (LISP)", draft-ietf-lisp-rfc6830bis-07 (work in progress), 1556 November 2017. 1558 [I-D.ietf-lisp-sec] 1559 Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D. 1560 Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-14 1561 (work in progress), October 2017. 1563 [I-D.ietf-lisp-signal-free-multicast] 1564 Moreno, V. and D. Farinacci, "Signal-Free LISP Multicast", 1565 draft-ietf-lisp-signal-free-multicast-07 (work in 1566 progress), November 2017. 1568 [I-D.lewis-lisp-gpe] 1569 Lewis, D., Lemon, J., Agarwal, P., Kreeger, L., Quinn, P., 1570 Smith, M., Yadav, N., and F. Maino, "LISP Generic Protocol 1571 Extension", draft-lewis-lisp-gpe-04 (work in progress), 1572 December 2017. 1574 [I-D.quinn-vxlan-gpe] 1575 Quinn, P., Manur, R., Kreeger, L., Lewis, D., Maino, F., 1576 Smith, M., Agarwal, P., Yong, L., Xu, X., Elzur, U., Garg, 1577 P., and D. Melman, "Generic Protocol Extension for VXLAN", 1578 draft-quinn-vxlan-gpe-04 (work in progress), February 1579 2015. 1581 [I-D.rodrigueznatal-lisp-pubsub] 1582 Rodriguez-Natal, A., Ermagan, V., Leong, J., Maino, F., 1583 Cabellos-Aparicio, A., Barkai, S., Farinacci, D., 1584 Boucadair, M., Jacquenet, C., and s. 1585 stefano.secci@lip6.fr, "Publish/Subscribe Functionality 1586 for LISP", draft-rodrigueznatal-lisp-pubsub-01 (work in 1587 progress), October 2017. 1589 [LISP-CONS] 1590 Brim, S., Chiappa, N., Farinacci, D., Fuller, V., Lewis, 1591 D., and D. Meyer, "LISP-CONS: A Content distribution 1592 Overlay Network Service for LISP", Work in Progress, April 1593 2008. 1595 [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- 1596 Hashing for Message Authentication", RFC 2104, 1597 DOI 10.17487/RFC2104, February 1997, 1598 . 1600 [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms 1601 (SHA and SHA-based HMAC and HKDF)", RFC 6234, 1602 DOI 10.17487/RFC6234, May 2011, 1603 . 1605 [RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, 1606 L., Sridhar, T., Bursell, M., and C. Wright, "Virtual 1607 eXtensible Local Area Network (VXLAN): A Framework for 1608 Overlaying Virtualized Layer 2 Networks over Layer 3 1609 Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014, 1610 . 1612 [RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID 1613 Separation Protocol (LISP) Threat Analysis", RFC 7835, 1614 DOI 10.17487/RFC7835, April 2016, 1615 . 1617 Appendix A. Acknowledgments 1619 The authors would like to thank Greg Schudel, Darrel Lewis, John 1620 Zwiebel, Andrew Partan, Dave Meyer, Isidor Kouvelas, Jesper Skriver, 1621 Fabio Maino, and members of the lisp@ietf.org mailing list for their 1622 feedback and helpful suggestions. 1624 Special thanks are due to Noel Chiappa for his extensive work on 1625 caching with LISP-CONS, some of which may be used by Map-Resolvers. 1627 Appendix B. Document Change Log 1629 [RFC Editor: Please delete this section on publication as RFC.] 1631 B.1. Changes to draft-ietf-lisp-rfc6833bis-07 1633 o Posted December 2017. 1635 o Make it more clear in a couple of places that RLOCs are used to 1636 locate ETRs more so than for Map-Server Map-Request forwarding. 1638 o Make it clear that "encapsualted" for a control message is an ECM 1639 based message. 1641 o Make it more clear what messages use source-port 4342 and which 1642 ones use destinatino-port 4342. 1644 o Don't make DDT references when the mapping transport system can be 1645 of any type and the referneced text is general to it. 1647 o Generalize text when referring to the format of an EID-prefix. 1648 Can use othe AFIs then IPv4 and IPv6. 1650 o Many editorial changes to clarify text. 1652 o Changed some "must", "should", and "may" to capitalized. 1654 o Added definitions for Map-Request and Map-Reply messages. 1656 o Ran document through IDNITs. 1658 B.2. Changes to draft-ietf-lisp-rfc6833bis-06 1660 o Posted October 2017. 1662 o Spec the I-bit to include the xTR-ID in a Map-Request message to 1663 be consistent with the Map-Register message and to anticipate the 1664 introduction of pubsub functionality to allow Map-Requests to 1665 subscribe to RLOC-set changes. 1667 o Updated references for individual submissions that became working 1668 group documents. 1670 o Updated references for working group documents that became RFCs. 1672 B.3. Changes to draft-ietf-lisp-rfc6833bis-05 1674 o Posted May 2017. 1676 o Update IANA Considerations section based on new requests from this 1677 document and changes from what was requested in [RFC6830]. 1679 B.4. Changes to draft-ietf-lisp-rfc6833bis-04 1681 o Posted May 2017. 1683 o Clarify how the Key-ID field is used in Map-Register and Map- 1684 Notify messages. Break the 16-bit field into a 8-bit Key-ID field 1685 and a 8-bit Algorithm-ID field. 1687 o Move the control-plane codepoints from the IANA Considerations 1688 section of RFC6830bis to the IANA Considerations section of this 1689 document. 1691 o In the "LISP Control Packet Type Allocations" section, indicate 1692 how message Types are IANA allocated and how experimental RFC8113 1693 sub-types should be requested. 1695 B.5. Changes to draft-ietf-lisp-rfc6833bis-03 1697 o Posted April 2017. 1699 o Add types 9-14 and specify they are not assigned. 1701 o Add the "LISP Shared Extension Message" type and point to RFC8113. 1703 B.6. Changes to draft-ietf-lisp-rfc6833bis-02 1705 o Posted April 2017. 1707 o Clarify that the LISP control-plane document defines how the LISP 1708 data-plane uses Map-Requests with either the SMR-bit set or the 1709 P-bit set supporting mapping updates and RLOC-probing. Indicating 1710 that other data-planes can use the same mechanisms or their own 1711 defined mechanisms to achieve the same functionality. 1713 B.7. Changes to draft-ietf-lisp-rfc6833bis-01 1715 o Posted March 2017. 1717 o Include references to new RFCs published. 1719 o Remove references to self. 1721 o Change references from RFC6830 to RFC6830bis. 1723 o Add two new action/reasons to a Map-Reply has posted to the LISP 1724 WG mailing list. 1726 o In intro section, add refernece to I-D.ietf-lisp-introduction. 1728 o Removed Open Issues section and references to "experimental". 1730 B.8. Changes to draft-ietf-lisp-rfc6833bis-00 1732 o Posted December 2016. 1734 o Created working group document from draft-farinacci-lisp 1735 -rfc6833-00 individual submission. No other changes made. 1737 B.9. Changes to draft-farinacci-lisp-rfc6833bis-00 1739 o Posted November 2016. 1741 o This is the initial draft to turn RFC 6833 into RFC 6833bis. 1743 o The document name has changed from the "Locator/ID Separation 1744 Protocol (LISP) Map-Server Interface" to the "Locator/ID 1745 Separation Protocol (LISP) Control-Plane". 1747 o The fundamental change was to move the control-plane messages from 1748 RFC 6830 to this document in an effort so any IETF developed or 1749 industry created data-plane could use the LISP mapping system and 1750 control-plane. 1752 o Update control-plane messages to incorporate what has been 1753 implemented in products during the early phase of LISP development 1754 but wasn't able to make it into RFC6830 and RFC6833 to make the 1755 Experimental RFC deadline. 1757 o Indicate there may be nodes in the mapping system that are not MRs 1758 or MSs, that is a ALT-node or a DDT-node. 1760 o Include LISP-DDT in Map-Resolver section and explain how they 1761 maintain a referral-cache. 1763 o Removed open issue about additional state in Map-Servers. With 1764 [RFC8111], Map-Servers have the same registration state and can 1765 give Map-Resolvers complete information in ms-ack Map-Referral 1766 messages. 1768 o Make reference to the LISP Threats Analysis RFC [RFC7835]. 1770 Authors' Addresses 1772 Vince Fuller 1773 Cisco Systems 1775 EMail: vaf@vaf.net 1777 Dino Farinacci 1778 Cisco Systems 1780 EMail: farinacci@gmail.com 1782 Albert Cabellos 1783 UPC/BarcelonaTech 1784 Campus Nord, C. Jordi Girona 1-3 1785 Barcelona, Catalunya 1786 Spain 1788 EMail: acabello@ac.upc.edu